<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>首页</title>
    <script src="../js/jquery-3.3.1.min.js"></script>
    <script>
        $(function () {
            $("#say").on("click", function () {
                alert("你好！");
            });
        });
    </script>
</head>
<body>
<p>你好</p>
<input id="say" type="button" value="点击"/>
</body>
</html>